Open AccessSite of Action of Inhibitors of Carbon Dioxide Assimilation by Whole Lettuce Chloroplasts
Author(s) -
Elchanan S. Bamberger,
Mordhay Avron
Publication year - 1975
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.56.4.481
Subject(s) - chloroplast , rubisco , carbon fixation , carbonic anhydrase , biochemistry , photosynthesis , chemistry , ribulose , enzyme , gene
The sites of action of several compounds, reported to inhibit CO(2) fixation by chloroplast preparations were located by developing assays in lettuce chloroplasts to test their effect on partial reactions of the carbon cycle and on carbonic anhydrase. The results indicated that: d, l-glyceral-dehyde and 5'-AMP inhibit phosphoribulose kinase or isomerase. 3-Phosphoglyceric acid and 6-phosphogluconate inhibit ribulose diphosphate carboxylase. Azide, Mg(2+), and nitrite inhibit the activity of carbonic anhydrase of lettuce chloroplasts and light-dependent CO(2) fixation by intact chloroplasts with similar sensitivities. None of these inhibited CO(2) fixation in ruptured chloroplasts. It is suggested that the inhibition by azide, nitrite, and magnesium ions of CO(2) fixation by intact chloroplasts is due to their inhibition of the activity of carbonic anhydrase.